Vulnerability-Lookup

GHSA-552V-QPHJ-5FJG

Vulnerability from github – Published: 2026-09-16 09:30 – Updated: 2026-09-16 15:30

Details

In the Linux kernel, the following vulnerability has been resolved:

vfio/pci: clear vdev->msi_perm after freeing it on init failure

vfio_msi_cap_len() lazily allocates the per-device MSI permission table:

vdev->msi_perm = kmalloc_obj(struct perm_bits, GFP_KERNEL_ACCOUNT);
if (!vdev->msi_perm)
    return -ENOMEM;

ret = init_pci_cap_msi_perm(vdev->msi_perm, len, flags);
if (ret) {
    kfree(vdev->msi_perm);
    return ret;     /* vdev->msi_perm left dangling */
}

When init_pci_cap_msi_perm() -> alloc_perm_bits() fails with -ENOMEM, the error path frees vdev->msi_perm but leaves the freed pointer stored in it. vdev->msi_perm is not re-zeroed later because struct vfio_pci_core_device is per-device and persists across open/close cycles, and the vfio_config_init() error path returns without calling vfio_config_free(). So the dangling pointer outlives the failed open.

That leads to two use-after-frees on the same device:

Reuse. The next vfio_config_init() sees the stale pointer at "if (vdev->msi_perm) return len;" and reuses the freed object. MSI config accesses in vfio_pci_config_rw_single() then dereference and call the freed perm->readfn / perm->writefn function pointers.
Double free. A later vfio_config_free() runs free_perm_bits() and kfree() on the already-freed object.

Fix it by NULLing vdev->msi_perm after the kfree(), matching the NULL-after-free discipline already used in free_perm_bits() and vfio_config_free().

BUG: KASAN: slab-use-after-free in vfio_pci_config_rw_single (drivers/vfio/pci/vfio_pci_config.c:1961) Read of size 8 at addr ffff88800fcc88d0 by task exploit/143 Call Trace: ... kasan_report (mm/kasan/report.c:595) vfio_pci_config_rw_single (drivers/vfio/pci/vfio_pci_config.c:1961) vfio_pci_config_rw (drivers/vfio/pci/vfio_pci_config.c:1986) vfio_pci_rw (drivers/vfio/pci/vfio_pci_core.c:1599) vfs_read (fs/read_write.c:572) __x64_sys_pread64 (fs/read_write.c:764) do_syscall_64 (arch/x86/entry/syscall_64.c:94) ...

Followed on device close by a double free of the same object:

Oops: general protection fault, probably for non-canonical address 0x1f63e0e8000008: 0000 [#1] SMP KASAN NOPTI RIP: 0010:kfree (mm/slub.c:6711) Call Trace: vfio_config_free (drivers/vfio/pci/vfio_pci_config.c:1861) vfio_pci_core_disable (drivers/vfio/pci/vfio_pci_core.c:685) vfio_pci_core_close_device (drivers/vfio/pci/vfio_pci_core.c:777) vfio_df_close (drivers/vfio/vfio_main.c:602) vfio_device_fops_release (drivers/vfio/vfio_main.c:648) __fput (fs/file_table.c:512) __x64_sys_close (fs/open.c:1496) do_syscall_64 (arch/x86/entry/syscall_64.c:94) ... Kernel panic - not syncing: Fatal exception

Severity

8.8 (High)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-89777"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-16T09:17:08Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nvfio/pci: clear vdev-\u003emsi_perm after freeing it on init failure\n\nvfio_msi_cap_len() lazily allocates the per-device MSI permission table:\n\n\tvdev-\u003emsi_perm = kmalloc_obj(struct perm_bits, GFP_KERNEL_ACCOUNT);\n\tif (!vdev-\u003emsi_perm)\n\t\treturn -ENOMEM;\n\n\tret = init_pci_cap_msi_perm(vdev-\u003emsi_perm, len, flags);\n\tif (ret) {\n\t\tkfree(vdev-\u003emsi_perm);\n\t\treturn ret;\t\t/* vdev-\u003emsi_perm left dangling */\n\t}\n\nWhen init_pci_cap_msi_perm() -\u003e alloc_perm_bits() fails with -ENOMEM, the\nerror path frees vdev-\u003emsi_perm but leaves the freed pointer stored in\nit. vdev-\u003emsi_perm is not re-zeroed later because struct\nvfio_pci_core_device is per-device and persists across open/close cycles,\nand the vfio_config_init() error path returns without calling\nvfio_config_free(). So the dangling pointer outlives the failed open.\n\nThat leads to two use-after-frees on the same device:\n\n1. Reuse. The next vfio_config_init() sees the stale pointer at\n   \"if (vdev-\u003emsi_perm) return len;\" and reuses the freed object. MSI\n   config accesses in vfio_pci_config_rw_single() then dereference and\n   call the freed perm-\u003ereadfn / perm-\u003ewritefn function pointers.\n\n2. Double free. A later vfio_config_free() runs free_perm_bits() and\n   kfree() on the already-freed object.\n\nFix it by NULLing vdev-\u003emsi_perm after the kfree(), matching the\nNULL-after-free discipline already used in free_perm_bits() and\nvfio_config_free().\n\n  BUG: KASAN: slab-use-after-free in vfio_pci_config_rw_single (drivers/vfio/pci/vfio_pci_config.c:1961)\n  Read of size 8 at addr ffff88800fcc88d0 by task exploit/143\n  Call Trace:\n   ...\n   kasan_report (mm/kasan/report.c:595)\n   vfio_pci_config_rw_single (drivers/vfio/pci/vfio_pci_config.c:1961)\n   vfio_pci_config_rw (drivers/vfio/pci/vfio_pci_config.c:1986)\n   vfio_pci_rw (drivers/vfio/pci/vfio_pci_core.c:1599)\n   vfs_read (fs/read_write.c:572)\n   __x64_sys_pread64 (fs/read_write.c:764)\n   do_syscall_64 (arch/x86/entry/syscall_64.c:94)\n   ...\n\nFollowed on device close by a double free of the same object:\n\n  Oops: general protection fault, probably for non-canonical address\n    0x1f63e0e8000008: 0000 [#1] SMP KASAN NOPTI\n  RIP: 0010:kfree (mm/slub.c:6711)\n  Call Trace:\n   vfio_config_free (drivers/vfio/pci/vfio_pci_config.c:1861)\n   vfio_pci_core_disable (drivers/vfio/pci/vfio_pci_core.c:685)\n   vfio_pci_core_close_device (drivers/vfio/pci/vfio_pci_core.c:777)\n   vfio_df_close (drivers/vfio/vfio_main.c:602)\n   vfio_device_fops_release (drivers/vfio/vfio_main.c:648)\n   __fput (fs/file_table.c:512)\n   __x64_sys_close (fs/open.c:1496)\n   do_syscall_64 (arch/x86/entry/syscall_64.c:94)\n   ...\n  Kernel panic - not syncing: Fatal exception",
  "id": "GHSA-552v-qphj-5fjg",
  "modified": "2026-09-16T15:30:57Z",
  "published": "2026-09-16T09:30:29Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89777"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/25cdd2a492d868cff1e519a60fe282909c52d385"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/533d0c5feef85ee6404b9f41d5564fac6971a008"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/812f1db7f0755a19ef16ecdc5cec51bcabc5eda5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d665a1688af7f8fefd7c0eb04f2a37122ce007f4"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dc77acfeb979dded39b247b60fef0399536bfa77"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/eb84cd81040e58dd05ac190f561f2115e3367249"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f0eea8f9013676b42289ec35941e848b8a543e19"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fda8fb7e8179561693a786a7af593f6b944a21c1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-89777 (GCVE-0-2026-89777)

Vulnerability from cvelistv5 – Published: 2026-09-16 08:48 – Updated: 2026-09-16 14:38

Title

vfio/pci: clear vdev->msi_perm after freeing it on init failure

Summary

In the Linux kernel, the following vulnerability has been resolved: vfio/pci: clear vdev->msi_perm after freeing it on init failure vfio_msi_cap_len() lazily allocates the per-device MSI permission table: vdev->msi_perm = kmalloc_obj(struct perm_bits, GFP_KERNEL_ACCOUNT); if (!vdev->msi_perm) return -ENOMEM; ret = init_pci_cap_msi_perm(vdev->msi_perm, len, flags); if (ret) { kfree(vdev->msi_perm); return ret; /* vdev->msi_perm left dangling */ } When init_pci_cap_msi_perm() -> alloc_perm_bits() fails with -ENOMEM, the error path frees vdev->msi_perm but leaves the freed pointer stored in it. vdev->msi_perm is not re-zeroed later because struct vfio_pci_core_device is per-device and persists across open/close cycles, and the vfio_config_init() error path returns without calling vfio_config_free(). So the dangling pointer outlives the failed open. That leads to two use-after-frees on the same device: 1. Reuse. The next vfio_config_init() sees the stale pointer at "if (vdev->msi_perm) return len;" and reuses the freed object. MSI config accesses in vfio_pci_config_rw_single() then dereference and call the freed perm->readfn / perm->writefn function pointers. 2. Double free. A later vfio_config_free() runs free_perm_bits() and kfree() on the already-freed object. Fix it by NULLing vdev->msi_perm after the kfree(), matching the NULL-after-free discipline already used in free_perm_bits() and vfio_config_free(). BUG: KASAN: slab-use-after-free in vfio_pci_config_rw_single (drivers/vfio/pci/vfio_pci_config.c:1961) Read of size 8 at addr ffff88800fcc88d0 by task exploit/143 Call Trace: ... kasan_report (mm/kasan/report.c:595) vfio_pci_config_rw_single (drivers/vfio/pci/vfio_pci_config.c:1961) vfio_pci_config_rw (drivers/vfio/pci/vfio_pci_config.c:1986) vfio_pci_rw (drivers/vfio/pci/vfio_pci_core.c:1599) vfs_read (fs/read_write.c:572) __x64_sys_pread64 (fs/read_write.c:764) do_syscall_64 (arch/x86/entry/syscall_64.c:94) ... Followed on device close by a double free of the same object: Oops: general protection fault, probably for non-canonical address 0x1f63e0e8000008: 0000 [#1] SMP KASAN NOPTI RIP: 0010:kfree (mm/slub.c:6711) Call Trace: vfio_config_free (drivers/vfio/pci/vfio_pci_config.c:1861) vfio_pci_core_disable (drivers/vfio/pci/vfio_pci_core.c:685) vfio_pci_core_close_device (drivers/vfio/pci/vfio_pci_core.c:777) vfio_df_close (drivers/vfio/vfio_main.c:602) vfio_device_fops_release (drivers/vfio/vfio_main.c:648) __fput (fs/file_table.c:512) __x64_sys_close (fs/open.c:1496) do_syscall_64 (arch/x86/entry/syscall_64.c:94) ... Kernel panic - not syncing: Fatal exception

Severity

8.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Assigner

Linux mitre root

References

8 references

URL	Tags
https://git.kernel.org/stable/c/eb84cd81040e58dd0…
https://git.kernel.org/stable/c/f0eea8f9013676b42…
https://git.kernel.org/stable/c/d665a1688af7f8fef…
https://git.kernel.org/stable/c/25cdd2a492d868cff…
https://git.kernel.org/stable/c/812f1db7f0755a19e…
https://git.kernel.org/stable/c/533d0c5feef85ee64…
https://git.kernel.org/stable/c/fda8fb7e817956169…
https://git.kernel.org/stable/c/dc77acfeb979dded3…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 30ea32ab1951c80c6113f300fce2c70cd12659e4 , < eb84cd81040e58dd05ac190f561f2115e3367249 (git) Affected: 30ea32ab1951c80c6113f300fce2c70cd12659e4 , < f0eea8f9013676b42289ec35941e848b8a543e19 (git) Affected: 30ea32ab1951c80c6113f300fce2c70cd12659e4 , < d665a1688af7f8fefd7c0eb04f2a37122ce007f4 (git) Affected: 30ea32ab1951c80c6113f300fce2c70cd12659e4 , < 25cdd2a492d868cff1e519a60fe282909c52d385 (git) Affected: 30ea32ab1951c80c6113f300fce2c70cd12659e4 , < 812f1db7f0755a19ef16ecdc5cec51bcabc5eda5 (git) Affected: 30ea32ab1951c80c6113f300fce2c70cd12659e4 , < 533d0c5feef85ee6404b9f41d5564fac6971a008 (git) Affected: 30ea32ab1951c80c6113f300fce2c70cd12659e4 , < fda8fb7e8179561693a786a7af593f6b944a21c1 (git) Affected: 30ea32ab1951c80c6113f300fce2c70cd12659e4 , < dc77acfeb979dded39b247b60fef0399536bfa77 (git) Affected: ac370e3d1f3b01519d2705cd5815d1c9d0a8812b (git) Affected: be363e27ec3c3a99793da2be6c07eafb95709c6b (git) Affected: f1b10ba5739440ca51d66f0b2949cead88d2dd02 (git) Affected: dde3433de9a067a33d67d65b9093cad3e043e49e (git) Affected: 4.4.203 , < 4.5 (semver) Affected: 4.9.203 , < 4.10 (semver) Affected: 4.14.155 , < 4.15 (semver) Affected: 4.19.85 , < 4.20 (semver)
Linux	Linux	Affected: 4.20 Unaffected: 0 , < 4.20 (semver) Unaffected: 5.10.270 , ≤ 5.10.* (semver) Unaffected: 5.15.221 , ≤ 5.15.* (semver) Unaffected: 6.1.188 , ≤ 6.1.* (semver) Unaffected: 6.6.157 , ≤ 6.6.* (semver) Unaffected: 6.12.110 , ≤ 6.12.* (semver) Unaffected: 6.18.52 , ≤ 6.18.* (semver) Unaffected: 7.2.6 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/vfio/pci/vfio_pci_config.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "eb84cd81040e58dd05ac190f561f2115e3367249",
              "status": "affected",
              "version": "30ea32ab1951c80c6113f300fce2c70cd12659e4",
              "versionType": "git"
            },
            {
              "lessThan": "f0eea8f9013676b42289ec35941e848b8a543e19",
              "status": "affected",
              "version": "30ea32ab1951c80c6113f300fce2c70cd12659e4",
              "versionType": "git"
            },
            {
              "lessThan": "d665a1688af7f8fefd7c0eb04f2a37122ce007f4",
              "status": "affected",
              "version": "30ea32ab1951c80c6113f300fce2c70cd12659e4",
              "versionType": "git"
            },
            {
              "lessThan": "25cdd2a492d868cff1e519a60fe282909c52d385",
              "status": "affected",
              "version": "30ea32ab1951c80c6113f300fce2c70cd12659e4",
              "versionType": "git"
            },
            {
              "lessThan": "812f1db7f0755a19ef16ecdc5cec51bcabc5eda5",
              "status": "affected",
              "version": "30ea32ab1951c80c6113f300fce2c70cd12659e4",
              "versionType": "git"
            },
            {
              "lessThan": "533d0c5feef85ee6404b9f41d5564fac6971a008",
              "status": "affected",
              "version": "30ea32ab1951c80c6113f300fce2c70cd12659e4",
              "versionType": "git"
            },
            {
              "lessThan": "fda8fb7e8179561693a786a7af593f6b944a21c1",
              "status": "affected",
              "version": "30ea32ab1951c80c6113f300fce2c70cd12659e4",
              "versionType": "git"
            },
            {
              "lessThan": "dc77acfeb979dded39b247b60fef0399536bfa77",
              "status": "affected",
              "version": "30ea32ab1951c80c6113f300fce2c70cd12659e4",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "ac370e3d1f3b01519d2705cd5815d1c9d0a8812b",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "be363e27ec3c3a99793da2be6c07eafb95709c6b",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "f1b10ba5739440ca51d66f0b2949cead88d2dd02",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "dde3433de9a067a33d67d65b9093cad3e043e49e",
              "versionType": "git"
            },
            {
              "lessThan": "4.5",
              "status": "affected",
              "version": "4.4.203",
              "versionType": "semver"
            },
            {
              "lessThan": "4.10",
              "status": "affected",
              "version": "4.9.203",
              "versionType": "semver"
            },
            {
              "lessThan": "4.15",
              "status": "affected",
              "version": "4.14.155",
              "versionType": "semver"
            },
            {
              "lessThan": "4.20",
              "status": "affected",
              "version": "4.19.85",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/vfio/pci/vfio_pci_config.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.20"
            },
            {
              "lessThan": "4.20",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.270",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.221",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.270",
                  "versionStartIncluding": "4.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.221",
                  "versionStartIncluding": "4.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.188",
                  "versionStartIncluding": "4.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.157",
                  "versionStartIncluding": "4.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.110",
                  "versionStartIncluding": "4.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.52",
                  "versionStartIncluding": "4.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.6",
                  "versionStartIncluding": "4.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "4.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "4.4.203",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "4.9.203",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "4.14.155",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "4.19.85",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvfio/pci: clear vdev-\u003emsi_perm after freeing it on init failure\n\nvfio_msi_cap_len() lazily allocates the per-device MSI permission table:\n\n\tvdev-\u003emsi_perm = kmalloc_obj(struct perm_bits, GFP_KERNEL_ACCOUNT);\n\tif (!vdev-\u003emsi_perm)\n\t\treturn -ENOMEM;\n\n\tret = init_pci_cap_msi_perm(vdev-\u003emsi_perm, len, flags);\n\tif (ret) {\n\t\tkfree(vdev-\u003emsi_perm);\n\t\treturn ret;\t\t/* vdev-\u003emsi_perm left dangling */\n\t}\n\nWhen init_pci_cap_msi_perm() -\u003e alloc_perm_bits() fails with -ENOMEM, the\nerror path frees vdev-\u003emsi_perm but leaves the freed pointer stored in\nit. vdev-\u003emsi_perm is not re-zeroed later because struct\nvfio_pci_core_device is per-device and persists across open/close cycles,\nand the vfio_config_init() error path returns without calling\nvfio_config_free(). So the dangling pointer outlives the failed open.\n\nThat leads to two use-after-frees on the same device:\n\n1. Reuse. The next vfio_config_init() sees the stale pointer at\n   \"if (vdev-\u003emsi_perm) return len;\" and reuses the freed object. MSI\n   config accesses in vfio_pci_config_rw_single() then dereference and\n   call the freed perm-\u003ereadfn / perm-\u003ewritefn function pointers.\n\n2. Double free. A later vfio_config_free() runs free_perm_bits() and\n   kfree() on the already-freed object.\n\nFix it by NULLing vdev-\u003emsi_perm after the kfree(), matching the\nNULL-after-free discipline already used in free_perm_bits() and\nvfio_config_free().\n\n  BUG: KASAN: slab-use-after-free in vfio_pci_config_rw_single (drivers/vfio/pci/vfio_pci_config.c:1961)\n  Read of size 8 at addr ffff88800fcc88d0 by task exploit/143\n  Call Trace:\n   ...\n   kasan_report (mm/kasan/report.c:595)\n   vfio_pci_config_rw_single (drivers/vfio/pci/vfio_pci_config.c:1961)\n   vfio_pci_config_rw (drivers/vfio/pci/vfio_pci_config.c:1986)\n   vfio_pci_rw (drivers/vfio/pci/vfio_pci_core.c:1599)\n   vfs_read (fs/read_write.c:572)\n   __x64_sys_pread64 (fs/read_write.c:764)\n   do_syscall_64 (arch/x86/entry/syscall_64.c:94)\n   ...\n\nFollowed on device close by a double free of the same object:\n\n  Oops: general protection fault, probably for non-canonical address\n    0x1f63e0e8000008: 0000 [#1] SMP KASAN NOPTI\n  RIP: 0010:kfree (mm/slub.c:6711)\n  Call Trace:\n   vfio_config_free (drivers/vfio/pci/vfio_pci_config.c:1861)\n   vfio_pci_core_disable (drivers/vfio/pci/vfio_pci_core.c:685)\n   vfio_pci_core_close_device (drivers/vfio/pci/vfio_pci_core.c:777)\n   vfio_df_close (drivers/vfio/vfio_main.c:602)\n   vfio_device_fops_release (drivers/vfio/vfio_main.c:648)\n   __fput (fs/file_table.c:512)\n   __x64_sys_close (fs/open.c:1496)\n   do_syscall_64 (arch/x86/entry/syscall_64.c:94)\n   ...\n  Kernel panic - not syncing: Fatal exception"
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The UAF is reached only via local VFIO char-device operations: open of /dev/vfio/$GROUP or /dev/vfio/devices/vfioN, then pread/pwrite of the PCI config region through vfio_pci_core_read/write into vfio_pci_config_rw_single(). There is no network or packet path into vfio_msi_cap_len().\nAC:L - After any failed vfio_config_init() plants the dangling vdev-\u003emsi_perm, the attacker retries GET_DEVICE_FD/BIND_IOMMUFD on the same persistent vdev and deterministically calls the freed perm-\u003ereadfn/writefn via MSI config accesses. The attacker controls that open/read sequence; no victim race or uncontrolled layout is required.\nPR:L - vfio_pci_core_enable() and vfio_pci_config_rw() have no capable() check on the normal IOMMU path (CAP_SYS_RAWIO is only for noiommu). Access is gated by /dev/vfio node permissions, which libvirt, kubevirt, and cloud GPU/NIC passthrough routinely grant to an unprivileged qemu user or tenant.\nUI:N - The attacker performs the VFIO open, retry, and MSI config-space pread/pwrite themselves. Prior admin binding of the PCI device to vfio-pci is deployment configuration, not victim interaction during exploitation.\nS:C - struct vfio_pci_core_device persists across open/close, so a failed open can leave a dangling msi_perm that a later tenant VM reuses. QEMU services guest PCI config cycles with VFIO pread/pwrite, so a passthrough guest can invoke the freed host function pointers and cross the VFIO/IOMMU guest-to-host boundary.\nC:H - The next successful open reuses the freed perm_bits and MSI config reads call perm-\u003ereadfn on that object. Reclaiming the slab slot yields an arbitrary kernel-read primitive, which CVSS kernel guidance scores High for use-after-free.\nI:H - MSI config writes call the freed perm-\u003ewritefn, and a later close double-frees the same object in vfio_config_free(). That UAF/double-free of a structure with function pointers is exploitable for arbitrary kernel write and control-flow hijack.\nA:H - The report shows a KASAN slab-use-after-free in vfio_pci_config_rw_single() followed by a general-protection fault in kfree() during vfio_config_free() that panics the host, so availability impact is a kernel oops/panic."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-16T14:38:28.611Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/eb84cd81040e58dd05ac190f561f2115e3367249"
        },
        {
          "url": "https://git.kernel.org/stable/c/f0eea8f9013676b42289ec35941e848b8a543e19"
        },
        {
          "url": "https://git.kernel.org/stable/c/d665a1688af7f8fefd7c0eb04f2a37122ce007f4"
        },
        {
          "url": "https://git.kernel.org/stable/c/25cdd2a492d868cff1e519a60fe282909c52d385"
        },
        {
          "url": "https://git.kernel.org/stable/c/812f1db7f0755a19ef16ecdc5cec51bcabc5eda5"
        },
        {
          "url": "https://git.kernel.org/stable/c/533d0c5feef85ee6404b9f41d5564fac6971a008"
        },
        {
          "url": "https://git.kernel.org/stable/c/fda8fb7e8179561693a786a7af593f6b944a21c1"
        },
        {
          "url": "https://git.kernel.org/stable/c/dc77acfeb979dded39b247b60fef0399536bfa77"
        }
      ],
      "title": "vfio/pci: clear vdev-\u003emsi_perm after freeing it on init failure",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89777",
    "datePublished": "2026-09-16T08:48:17.754Z",
    "dateReserved": "2026-09-11T19:38:34.765Z",
    "dateUpdated": "2026-09-16T14:38:28.611Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.